The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in the present disclosure and are not admitted to be prior art by inclusion in this section.
Machine-to-machine (“M2M”) wireless machines or devices (hereafter referred to as “devices”) may communicate primarily or exclusively with other machines or devices, with little or no human intervention. Examples of M2M devices may include wireless weather sensors, assembly line sensors, meters to track vehicles of a fleet, and so forth. In many cases these devices may log onto a wireless network and communicate with a network server, e.g., over the Internet. In parlance of the 3GPP Long Term Evolution (“LTE”) Release 10 (March 2011) (the “LTE Standard”), M2M may alternatively be referred to as “machine type communications” (“MTC”). M2M devices may also be used with the IEEE 802.16 standard, IEEE Std. 802.16-2009, published May 29, 2009 (“WiMAX”), as well as in Third Generation (“3G”) networks.
When an M2M device reenters a network, for example, after being in standby or idle mode, a typical network reentry process may include downlink synchronization, uplink synchronization using random access, channel allocation and registration. However, where a large number of M2M devices are to perform uplink synchronization using a random access mechanism, there may be collisions. These collisions may reduce uplink synchronization efficiency and ultimately, the network reentry efficiency.